1. Field of the Invention
The present invention relates to an improved and efficient method of cleaning a cat litter box having a manually or power driven crankshaft which imparts a movement force to a perforated sifting screen which scrapes along the bottom of the litter box and through the cat litter to remove cat waste from the litter and then dispose of the waste in a container which is integral with the litter box.
2. Discussion of Background
In the prior art, various cat litter box cleaning devices are known which facilitate the removal of cat waste from the litter box. One such apparatus is disclosed in U.S. Pat. No. 4,190,525 to MenZel. Such an apparatus is shown in FIG. 16 of the instant application. In this device, a trough shaped container 104 is provided with a curved bottom surface and an open top. In operation and in order to remove cat waste from the litter, a screen member 122 is provided which scrapes along the bottom curved surface of the litter box and sifts through the litter while retaining the larger waste particulate matter. The means for providing movement of the screen member 122 through the litter is a crank mechanism 112 mounted on a container 104 which includes a crankshaft 114, and crank handle 118. The crank mechanism is rotatable through a full 360.degree. radius and when the cat's waste has been sifted out by screen member 122, the screen member 122 can be removed from the crank mechanism 112 and carried to a disposal, such as a waste basket or toilet.
The prior art litter box cleaning device described above has significant disadvantages. As is apparent, the screen member 122 has to be manually detached and carried by the cat owner each time the litter box is sifted clean. This is an unpleasant task for the owner who is not inclined to touch the screen member 122 after such has been passed through the soiled litter, due to germs or waste matter on the screen member. The owner would be required to wear gloves or use paper towels in order to avoid his/her fingers from contacting with a dirty screen member, thus giving rise to an inconvenience.
Another main drawback of the device is that the litter box has an open top portion which can lead to an unpleasant odor and nuisance to the cat owner. Also, the open surface of the litter box may lead to a portion of the litter being strewn outside of the box by the cat when it paws the litter over the waste after eliminating.
A second cat litter disposal device is disclosed in U.S. Pat. No. 4,787,334, and illustrated in prior art FIG. 17 of the instant application, which shows an elongated base 110 for the cat to eliminate on, which base 110 supports a sheath 116 covered with a layer of litter 142. After the cat has soiled the litter, a crank 130 located on a receiver 144 is rotated to carry the soiled litter into the receiver and to feed an additional length of sheath 116, covered by a layer of litter 142, out onto base 110.
This device suffers a similar disadvantage as the previously described one in that it has an open top surface. More significantly and problematic, the device requires a large amount of space which may limit the number of places where it can be stored.
A third device, disclosed in U.S. Pat. No. 4,854,267, has the general drawback that it is quite complex in structure and this results in the problem of a more costly product.
Thus, there is a need in the art for an automatic or semiautomatic cat litter box with a cleaning mechanism which can remove cat waste from the box with a relatively easy-to-use apparatus which is simple in design and less costly to manufacture.